Elastic sheet for absorbent article and absorbent article

Abstract

An elastic sheet for an absorbent article includes a first fibrous layer disposed on a first surface of the elastic sheet, a second fibrous layer disposed on a second surface of the elastic sheet opposite to the first surface, and contractible elastic members secured between the first fibrous layer and the second fibrous layer. The first fibrous layer and the second fibrous layer each include continuous fibers of thermoplastic and gathers formed between adjacent ones of the elastic members. The gathers are disposed in an intersecting direction intersecting with a direction in which the elastic members extend. An average flexural rigidity value of the first fibrous layer and the second fibrous layer in accordance with a KES method is 0.0035×10−4 to 0.022×10−4 (N·m2/m). A thickness under a compression load to the gathers in accordance with the KES method is 0.22 to 1.5 mm.

What is claimed is: 
     
       1. The elastic sheet for an absorbent article comprising:
 a first fibrous layer comprising a first surface of the elastic sheet; 
 a second fibrous layer comprising a second surface of the elastic sheet opposite the first surface; and 
 contractible elastic members extending in a first direction and secured between the first fibrous layer and the second fibrous layer, the first fibrous layer and the second fibrous layer having a plurality of gathers disposed in a second direction intersecting the first direction and also formed between elastic members, 
 wherein the first fibrous layer comprises a spun-bonded or spun-melt nonwoven fabric including continuous polyethylene fibers and wherein a second fibrous layer comprises a spun-bonded or spun-melt nonwoven fabric including continuous polyethylene and/or polypropylene fibers, 
 an average flexural rigidity value of the first fibrous layer and second fibrous layer is 0.0035×10 −4  to 0.022×10 −4  N·m 2 /m as measured according to a Kawabata Evaluation System (KES) method, and 
 a thickness of 0.22 to 1.5 mm under a compression load of 49.03 hPa to the gathers as measured according to a KES method. 
 
     
     
       2. The elastic sheet according to  claim 1 , comprising an initial thickness of 2.70 to 4.70 mm under a micro-load to the gathers of 0.49 hPa according to the KES method. 
     
     
       3. The elastic sheet according to  claim 1 , wherein
 the gathers between adjacent elastic members are formed such that a convexity is formed as viewed from the first surface and a concavity is formed as viewed from the second surface. 
 
     
     
       4. The elastic sheet according to  claim 1 , wherein
 a compression workload under the compression load to the gathers is 0.236 to 5.0 N·m/m 2 , and 
 a compression resilience rate under the compression load to the gathers is 19 to 36%. 
 
     
     
       5. The elastic sheet according to  claim 1 , wherein
 the first fibrous layer and the second fibrous layer each comprise fused parts, where the continuous fibers are fused, and non-fused parts, wherein a rigidity difference between the fusion parts and non-fused parts in the second fibrous layer is larger than a rigidity difference between the fused parts and the non-fused parts. 
 
     
     
       6. The elastic sheet according to  claim 1 , wherein
 a basis weight of each of the first fibrous layer and the second fibrous layer is 10 to 30 g/m 2 , 
 a density of each of the first fibrous layer and the second fibrous layer is 0.04 to 0.15 g/m 3 , and 
 a pitch between the elastic members in the intersecting direction is 2.0 to 12.0 mm. 
 
     
     
       7. The elastic sheet according to  claim 1 , wherein a fineness of the polyethylene fibers is 1.5 to 4.0 dtex and a fineness of the polypropylene fibers, if present, is 0.9 to 2.5 dtex. 
     
     
       8. An absorbent article comprising the elastic sheet according to  claim 1 , wherein
 the first surface is a skin-facing surface, and 
 the second surface is a non-skin facing surface opposite to the skin facing surface. 
 
     
     
       9. The absorbent article according to  claim 8 , wherein
 the absorbent article is a disposable diaper having a front waist region, a rear waist region, and a crotch region, wherein 
 the elastic sheet forms one or more of a waist elastic sheet forming the front and rear waist regions, a leg elastic sheet disposed along a leg opening edge in the crotch region, and a leakage barrier flap extending from the crotch region to the front and rear waist regions. 
 
     
     
       10. The elastic sheet for an absorbent article comprising:
 a first fibrous layer comprising a first surface of the elastic sheet; 
 a second fibrous layer comprising a second surface of the elastic sheet opposite the first surface; and 
 contractible elastic members extending in a first direction and secured between the first fibrous layer and the second fibrous layer, the first fibrous layer and the second fibrous layer having a plurality of gathers disposed in a second direction intersecting the first direction and also formed such that a convexity is formed as viewed from the first surface and a concavity is formed as viewed from the second surface between adjacent elastic members, 
 wherein the first fibrous layer and the second fibrous layer comprise a spun-bonded or spun-melt nonwoven fabric including continuous thermoplastic fibers; 
 an average flexural rigidity value of the first fibrous layer and second fibrous layer is 0.0035×10 −4  to 0.022×10 −4  N·m 2 /m as measured according to a Kawabata Evaluation System (KES) method, and 
 a thickness under a compression load of 49.03 hPa to the gathers is 0.22 to 1.5 mm as measured according to a KES method. 
 
     
     
       11. The elastic sheet according to  claim 10 , comprising an initial thickness of 2.70 to 4.70 mm under a micro-load to the gathers of 0.49 hPa according to the KES method. 
     
     
       12. The elastic sheet according to  claim 10 , wherein
 wherein the thermoplastic fibers are polyethylene fibers for the first fibrous layer and wherein the thermoplastic fibers are polyethylene and/or polypropylene fibers for the second fibrous layer. 
 
     
     
       13. The elastic sheet according to  claim 10 , wherein
 a compression workload under the compression load to the gathers is 0.236 to 5.0 N·m/m 2  , and 
 a compression resilience rate under the compression load to the gathers is 19 to 36%. 
 
     
     
       14. The elastic sheet according to  claim 10 , wherein
 the first fibrous layer and the second fibrous layer each comprise fused parts, where the continuous fibers are fused, and non-fused parts, wherein a rigidity difference between the fusion parts and non-fused parts in the second fibrous layer is larger than a rigidity difference between the fused parts and the non-fused parts. 
 
     
     
       15. The elastic sheet according to  claim 10 , wherein
 a basis weight of each of the first fibrous layer and the second fibrous layer is 10 to 30 g/m 2 , 
 a density of each of the first fibrous layer and the second fibrous layer is 0.04 to 0.15 g/m 3 , and 
 a pitch between the elastic members in the intersecting direction is 2.0 to 12.0 mm. 
 
     
     
       16. The elastic sheet according to  claim 12 , wherein a fineness of the polyethylene fibers is 1.5 to 4.0 dtex and a fineness of the polypropylene fibers, if present, is 0.9 to 2.5 dtex. 
     
     
       17. An absorbent article comprising the elastic sheet according to  claim 10 , wherein
 the first surface is a skin-facing surface, and 
 the second surface is a non-skin facing surface opposite to the skin facing surface. 
 
     
     
       18. The absorbent article according to  claim 17 , wherein
 the absorbent article is a disposable diaper having a front waist region, a rear waist region, and a crotch region, wherein 
 the elastic sheet forms one or more of a waist elastic sheet forming the front and rear waist regions, a leg elastic sheet disposed along a leg opening edge in the crotch region, and a leakage barrier flap extending from the crotch region to the front and rear waist regions. 
 
     
     
       19. The elastic sheet for an absorbent article comprising:
 a first fibrous layer comprising a first surface of the elastic sheet; 
 a second fibrous layer comprising a second surface of the elastic sheet opposite the first surface; and 
 contractible elastic members extending in a first direction and secured between the first fibrous layer and the second fibrous layer, the first fibrous layer and the second fibrous layer having a plurality of gathers disposed in a second direction intersecting the first direction and also formed between elastic members, 
 wherein the first fibrous layer and the second fibrous layer comprise a spun-bonded or spun-melt nonwoven fabric including continuous thermoplastic fibers, wherein the thermoplastic fibers comprise polyethylene fibers in at least one of the first fibrous layer and the second fibrous layer; 
 an average flexural rigidity value of the first fibrous layer and second fibrous layer is 0.0035×10 −4  to 0.022×10 −4  N·m 2 /m as measured according to a Kawabata Evaluation System (KES) method, and 
 a thickness of 2.70 to 4.70 mm under a micro-load of 0.49 hPa to the gathers and a thickness of 0.22 to 1.5 mm under a compression load of 49.03 hPa to the gathers as measured according to a KES method. 
 
     
     
       20. An absorbent article comprising the elastic sheet according to  claim 19 , wherein
 the first surface is a skin-facing surface, and 
 the second surface is a non-skin facing surface opposite to the skin facing surface.